Catalytic conversion of hydrocarbons with a silica-alumina and crystalline zeolite catalyst composite



A g- 1964 E. v. BERGSTROM 3,143,491

CATALYTIC CONVERSION OF HYDROCARBONS WITH A SILICA-ALUMINA AND CRYSTAL-LINE ZEOLITE CATALYST COMPOSITE Filed Feb. 20, 1962 2 Sheets-Sheet 2 F/ 6 2 6474A, ys'r 504m; m/vK LIFT LIF P07 INVENTOR.

Affomey United States Patent 3,143,491 CATALYTEC CCNVERSIGN OF HYDRO-CAREGNS WITH A SELICA-ALUMINA AND CRYfiTALLlNE ZEGLITE CATALYST COMPQSHE Eric V. Bergstrorn, Byram, Conn, assignor to Socony Mobil 0i! Company, Inc, a corporation of New York Filed Feb. 29, 1962, Ser. No. 174,553 1 Claim. (Cl. 20874) This invention is concerned with the direct working up of crude oil into a spectrum of products eminently suited for markets wherein the high quality automotive fuel product does not dominate the market, where lighter than gasoline fractions encounter a promising demand, and where demand for residual fuel oil is either light or met to a great degree by bottoms from the simple fractionation of cheap or refractory crude oils.

It is based in part upon the characteristics of newly available catalytic materials, and in part upon departures from conversion practices that have heretofore been conventional.

It has for its object the handling of crude oil and intermediate products to provide an amount of high quality gasoline relatively smaller than now considered conventional, an elimination of residual fuel oil, larger amounts of products lighter than gasoline, and distillate fuel oil products.

It has for an object the provision of a unitary and balanced process capable of producing such products with a maximum economy of heat, a minimum of apparatus, and with its various steps properly interrelated.

For a further object, it has the utilization in such a process of new and more active catalysts than those heretofore available.

These and other objects and the method of accomplishing them will be understood by consideration of the following description of the invention and from the drawings attached to and made a part of this specification.

As will be observed, the process is a moving bed catalytic conversion process, making use of the same catalyst for two conversions, one of gasoline and lighter products, the other for conversion of gas oil plus residual products, with a common regeneration zone.

In the drawings, which are diagrammatic flow sheets:

FIGURE 1 sets forth one version with one stream of catalyst through the light product operation and another through the gas oil-residuum operation.

FIGURE 2 sets forth another version, with all catalyst flowing serially through a light product operation and then through a gas oil-residuum cracking operation.

In FIGURE 1, crude oil (whole crude) heated (in a heater not shown) to a temperature of the order of 700750 F., enters through pipe 3 into crude fractionator 4, there to be divided into an overhead product comprising straight-run gasoline and hydrocarbons lighter than gasoline which pass out through pipe 5, a kerosine cut or product of similar boiling range taken as a side stream through pipe 6 and a residual product, comprising all portions of the crude heavier than kerosine, leaving as a distillation residue through pipe 7. In case the material of kerosine-like boiling range found in the original crude is unsatisfactory for kerosine manufacture or for use as a distillate fuel, it may be combined with the residuum, withdrawn through pipe 7.

The straight-run gasoline and gas component of the crude passes through pipe into a reactor 8 where it is contacted with a catalyst, which enters through conduit 9 and leaves through conduit 10. The operation conducted in reactor 8 is essentially one of catalytic reforming in the absence of added hydrogen and is later referred to herein, as is the catalyst. Efiiuent from reactor 8 departs through pipe 11.

3,143,491 Patented Aug. 4, 1964 Reduced crude, i.e., crude devoid of lighter constituents, also referred to herein as crude residue, passes through pipe 7 to a cracking reactor 12, where it contacts catalyst supplied through conduit 13, and eflluent from this cracking operation passes out through pipe 14.

Catalyst departing from reactor 12 through conduits 15 enters multi-compartment regenerator kiln 16S and departs therefrom through conduit 17 to enter air-lift feed pct 18, whence it, together with catalyst coming from reactor 8 through conduit 10, is lifted through lift-pipe 19 to the catalyst surge and supply vessel 21 Under conditions discussed below the effluent from reactor 8, flowing in pipe 11, together with efiiuent from reactor 12, flowing in pipe 14, enter a fractionation system diagrammatically designated by vessel 21. From the top of this vessel, products lighter than gasoline depart through pipe 22, gasoline through pipe 23, cuts of the nature of light gas oil, distillate fuel oil, etc. (if desired), through pipe 24, and heavy gas oil fractions through pipe 25. This heavy gas oil may be diverted to fuel oil sales, as through pipe 26, to plant fuel, as through pipe 27, or even recycled to cracking, as through pipe 28.

Under other conditions discussed below, the effluent from reactor 12 may be handled alone in fractionation system 21, while the efiiuent from reactor 8 will be taken through pipe 2? to a second fractionation system designated by vessel 31), from which overhead products lighter than gasoline depart through pipe 31, gasoline product through pipe 32, and heavier than gasoline through pipe 33 to be disposed of as a product, as through pipe 34, or for internal plant disposition as through pipe 35, or even recycled to reactor 12 as through pipe 36.

This inventive concept is based upon the capabilities of newly developed catalytic materials. These materials are composite, one ingredient being the amorphous acidic silica-alumina cracking catalyst conventionally known, which may be produced, as is known by co-gelation procedures, by co-precipitation procedures, both involving the combination of selected proportions of silica and alumina in a material which is finished by base exchange and calcination. Similar materials may be prepared from selected clays. The characterizing material of the composite which gives rise to the desirable features of the newly developed catalyst is an alumino-silicate material of ordered structure, of generally zeolitic nature, capable of base exchange, preferably treated to arrive at an acidic or H form by removal of part or all of the alkali metal content of the salt form of the zeolitic material, and frequently used in a form in which a partial base exchange has been effected with rare-earth salts.

As an example of such alumino-silicate material, there may be cited a compound prepared by base-exchanging an alumino-siiicate described in United States Patent 2,882,244 with a solution of rare-earth chlorides, in known manner, to produce a product having about 1.0 to 1.5% (wt.) of sodium and about 25% (wt.) of rare-earth elements calculated as Re O When this is incorporated in the composite with acidic amorphous silica-alumina to the extent of from about 1% (wt.) upwards, preferably about 5 to 15% (wt.), followed by appropriate forming and finishing techniques, catalytic composites as herein used are formed.

In some cases, finely divided alumina, or finely divided solid material of the same composition as the composite may be added for control of physical properties.

These catalytic materials are herein spoken of as a catalytic composite of a microporous amorphous acidic silica-alumina cracking catalyst and an alumino-silicate material of ordered structure and capable of base exchange. Such catalytic materials, themselves, form no part of this invention except as it is directed to methods for their economic use.

These catalytic materials have considerably greater activity than the conventional silica-alumina catalysts and may be hereinafter spoken of as high activity catalysts. These catalysts have considerably greater capability of handling residual oil cracking, are heat stable to regenerating temperatures of the order of 12001350 F., and have good capability for a reforming type of reaction with straight-run gasoline constituents at relatively low temperatures and in the absence of added hydrogen, in which relatively small amounts of coke are deposited.

Referring to FIGURE 1, a typical operation on Kuwait- Sahara crude oil mixture of about 37 API gravity with this arrangement, with the stream from reactor 8 combined with that from reactor 12 and fractionated at 21, there would be produced as overhead at 22 about by volume of the crude charged as products lighter than gasoline, to be separated into about 3% (on crude), as city gas, the remainder to be sold as liquefied petroleum gas or, if desired, a cut of C hydrocarbons may be removed for alkylation. About 3035% by volume of the crude charged would be gasoline of good quality, and the streams of intermediate distillate nature withdrawn at pipes 6 and 24 would amount together to about 30% by volume of the crude charged. The major change would be that no residual fuel oil is produced, but instead there is produced at 25 a heavy gas oil, and in an amount about two-thirds of the residual fuel oil produced by conventional operation.

If it is desired to produce a premium gasoline, the stream from reactors (the temperature of which may be controlled by catalyst cooler 37) is diverted to a second fractionation system as at 30. This operation will result in about the same total amount of gasoline, divided between a high quality premium gasoline and a regular gasoline of quality below that of the composite stream, but still quite acceptable in quality.

An interesting method of utilizing the capability of this high activity catalyst is shown in FIGURE 2.

In this operation, crude oil, heated in a heater not shown, to a temperature of 700 F. to 750 F. enters at pipe 38 to fractionator 39, with an overhead composed of straight-run gasoline and lighter products departing through pipe 40, a side stream of kerosene or diesel fuel nature, as before leaving through pipe 41 and a distillation residue, combining all fractions heavier than taken through side stream 41, departs at 42.

The overhead product in pipe 40 passes through a trim or temperature adjusting heater 43 and then through pipe 44 into reactor 45. Efiluent from reactor 45 is led through pipe 46 into a fractionation system in dicated by vessel 47.

The residual material in pipe 42 passes through pipe 48 into reactor 49, and efliuent from this reactor passes through pipe 50, normally to be combined with that in pipe 46 and so into fractionation at 47.

In fractionation at 47, there is produced an overhead fraction of products lighter than gasoline departing through 51, gasoline, as at 52, light gas oil or distillate fuel as at 53, and heavy gas oil as at 54. This heavy gas oil may be diverted to fuel oil sales, as through pip 55, to plant fuel as through pipe 56, or even recycled to cracking, as through pipe 57.

If it is desired to produce premium gasoline, a dual fractionation system is provided, with efliuent from reactor 49 passing through pipes 50 and 58 to a fractionation system indicated by vessel 59, with lighter than gasoline overhead departing through pipe 60, gasoline through pipe 61, light gas oil, etc., through pipe 62, and

generation kiln 69. Regenerated hot catalyst passes through conduits 70 and 71 into lift pot 72, and through air-lift conduit 73 to catalyst surge and supply vessel 74.

In operating according to the scheme shown in FIG- URE 2, with production of high quality premium gasoline, charging Kuwait-Sahara mixed crude oil (about 37 API), the temperatures of operation will be about as follows:

Crude oil to fractionater 39, 700 F.750 F.;'light overhead from fractionator 39 through trim furnace to reactor 45, 750 F.800 F.; catalyst from regenerator in catalyst surge tank 74, 1250 F.; top of reactor 45, 1200 F.-1250 F; catalyst at point between reactors 45 and 49, 1050 F.

Pressures in the reactors 45 and 49 will be of the order of 1525 p.s.i.g.

Yields from this operation would be approximately as follows: Permanently gaseous materials lighter than propane, i.e., city gas, about 12% by volume on crude (as equivalent barrels); about 14% of a C -C cut to be sold as liquefied petroleum gas (from which,- if desired, a butane-butene cut could be recovered for alkylation); about 14% by volume of premium gasoline; about 12% (by volume) of regular grade gasoline; about 15% (volume) of automobile diesel fuel; about 11% (volume) of light distillate fuel oil; and about 15% (volume) of heavier distillate fuel oil. The remainder, about 7% by volume of the original crude, is practically all coke, burned off in regenerator 69, providing, in hot catalyst, a major portion of the heat consumed in the operation.

Another interesting operation which may be conducted in the set-up of FIGURE 2 is the charging of a straight run gasoline fraction direct through trim heater 43 by pipe 75 and thence to reactor 45, and a crude residue from a preheater (not shown) at about 700-750 F. through pipe 76 and pipes 42 and 48 to reactor 49. The straight run gasoline will be converted into light products and high quality gasoline in reactor 45 as before, while the crude residuum will undergo conversion in reactor 49 the regenerator, and supplying reactor heat.

heavy gas oil through pipe 63, to disposal, as before to It will be noted that the low coke-forming capability of this catalyst composite where used for the conversion of low boiling materials is taken advantage of in significant process simplifications.

In the operation of FIGURE 1, where the object of gasoline conversion is basically reforming, the eflluent catalyst composite is sufliciently low in coke content to permit re-use when combined with the regenerated catalyst composite coming from regenerator 16'. In the operation of FIGURE 2, where the object of gasoline conversion is basically a combination of light hydrocarbon gas production and reforming in reactor 44, the entire cycling catalyst composite is used and flows from 44 into reactor 49.

i This feature permits significant economy of investment and operation in that only a single catalyst lift operation is necessary. A further feature of this combination of operations is that regenerator heat, as sensible heat of catalyst composite, is available for the heat demands: of reactor 8 in FIGURE 1 operation and of -reactors 44 and 49 in FIGURE 2 operation.

It will be obvious from the above that this novel method for the conversion of petroleum and petroleum fractions has advantages of major importance for those areas and situations where the production of gaseous fractions and fractions lighter than gasoline, as well as the non-production of residual fuels are of importance. It is also noted that the capabilities of the process, in its various embodiments, is directed to areas heretofore carefully avoided in the conventional conversion of petroleum.

I claim:

That method for the catalytic treatment of petroleum to convert it substantially to products of gas oil and lower boiling nature, including gasoline of good anti-knock quality which comprises:

vaporizing and separating from the crude oil a straightrun gasoline fraction which includes any material boiling below gasoline,

subjecting this straight-run gasoline fraction to contact with a catalyst comprising a composite of a microporous amorphous silica-alumina cracking catalyst and crystalline aluminosilicate at temperatures of the order of 1000 F. to 1200 F. to convert a substantial portion thereof to materials boiling below the gasoline boiling range,

passing the residual remainder of the crude oil into contact with a similar catalyst at temperatures of the order of 800 F. to 1000 F. to convert it to products lighter than gasoline, gasoline, gas oil fractions and coke,

and fractionating the products of said conversions,

the said conversion catalyst being circulated cyclically through the several conversion zones, and regenerated by burning after withdrawal from the crude residue conversion zone,

the entire regenerated catalyst being introduced to the straight-run gasoline conversion zone at a temperature of the order of 1250" F., and after exit from such zone the entire catalyst stream is then introduced directly into the crude residue conversion zone.

References Cited in the file of this patent UNITED STATES PATENTS 

